Process of separating the products of the destructive distillation of wood.



T. H. KENNEDY & F. J. HEGKEL. PROCESS O]? SEPABATING THE PRODUCTS OF THE DESTBUGTIVE DISTILLATION 0P WOOD.

APPLICATION FILED JAN. 6, 1910. 969,635.

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uclkarv I [NVENTOR5 SUB 000M T. H. KENNEDY & F. J. HEGKEL. rnocnss or SBPABATING THE PRODUOTS OF THE DESTRUGTIVE DISTILLATION OF WOOD.

APPLICATION FILED JAN. 6, 1910 969,635. Patented Sept. 6, 1910.-

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mohtk-dt INVENTORS Attorney) WITNESSES I To all whom it may concern:

UNITED STATES PATENT OFFICE.

THOMAS H. KENNEDY AND FRED J. HECKEL, OF BRADFORD, PENNSYLVANIA; SAID HECKEL ASSIG-NOR TO SAID KENNEDY.

PROCESS OF SEPARATING THE PRODUCTS THE DESTRUCTIVE DISTILLATION OF.

. WOOD.

Be it known that we, THOMAS H. KEN- NEDY and FRED J. HECKEL, citizens of the United States, residing at Bradford, in the county of McKean and State of Pennsylvania, have invented certain new and useful Improvements in Processes of Separating the Productsv of the Destructive Distillation of Wood; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

Our invention relates to an improved process for separating the products of the destructive distillation of wood, such as hard wood, or the wood from the deciduous trees, the Woods most generally treated being beech, birch and maple. In the present process in general use commercially for this purpose, the main products obtained are wood alcohol and acetic acid in the form of gray acetate of lime, of about 80% purity. As by roducts tar and oils are also obtained. gharcoal is of course obtained from the retorts. In separating the products of the destructive distillation of such wood, as at present practiced, we have discovered that considerable amounts of acid is recovered, and in practice we find that by the use of our process we are able to increase the amount of acetate of lime recovered, by about fifteen per cent. for any given quantity of wood treated.

The novel features of our invention are fully set forth in the accompanying spec1fi-' cation, reference being had to the accompanying drawings, and said invention is fully (1180105811. in the following description and claims.

Referring to the saiddrawings, Flgure -1 represents a diagrammatic view of one form of apparatus for carrying our improved process into effect. Fig. 1 is a detail of a part of Fig. 1 showing a slight modification of the arrangement .of the parts. Fig. 2 is Specification of Letters Patent.

Application filed January 6, 1910. Serial No. 536,631.

a diagrammatic viewof a modified form of apparatus for the same purpose.

Patented Sept. 6, 1910.

In the drawings,1 re resents a retort, or I oveng in which the woo under treatment is placed, in any suitable manner, and subjected to destructive heat, in any usual or preferred way, so as to destructivel While the woods generally treate are birch,

beech and maple, as before stated, other woods of the deciduous trees may be employed with advantageous results. .The vapors pass from the retort 1, into a condenser. C, of any usual or preferred construction from which the condensed retort distill it;

liquor passes into settling tanks 2, 3, 4 and I 5 of which there may be any desired number, a pipe 0 being provided for the escape of the non-condensable wood gas, between the condenser and settling tanks. In these settling tanks the raw tars and oils separate from the pyroligneous acid liquor, the lat- -ter, containing some tarry matters, being drawn ofi into one or more stills (generally of copper) one of Whichis indicated at 6. This still is heated preferably by means of a steam coil H, as shown, and is run continuously for a considerable period at a time, as a week, the fresh pyroli eous acid liquor being admitted from t e settling tanks from time to time. from the copper 'still 6 which contains acetic acid and alcohol, passes-to a condenser C and from said condenser it is drawn off into a storage tank 7 (or tanks) The filter F shown in Fig. 1, the use of which is hereinafter described, is at this time ordinarily cuto'if from the pipe leadin from the condenser, by a suitable valve mdicated at 40 in Fig. 1. The tarry matters collect and remain in the still.

The distillate from the copper still is mixed with an alkali, preferably lime, agi tated and distilled. In the use of the apparatus shown in the drawing the distillate is drawn from the storage tank 7 into a receptacle 8, and is mixed with an alkali (preferably lime in the form of slaked lime, or fiiilk of lime) and agitated in any suitable way, by means of a stirring device, or by The distillate the injection of compressed air, through a where it is again distilled by means of heat applied preferably from a steam coil H, as shown. The vapors from the lime lee still pass into a condenser C where they are condensed as weak alcohol which is con ducted away, and preferably redistilled to produce commercial wood alcohol of from 80 to 84 per cent.

The-residue from the lime lee still 9 is discharged into a settling tank 10 where the solution of acetate of lime is separated from the solid matter, and impurities (which in the form of sludge is subsequently discharged as waste) and is' then drawn off into an evaporating pan 11, of any suitable form,

and heated by steam coils (not shown), or

by waste heat from the retort, or direct heat, as preferred, and the solution is evaporated todryness, and is then discharged upon a drying floor 12, as gray acetate of lime, of substantially 80 per cent. purity.

Returning now to the first settling tanks 2, 3, 4 and 5, it will be noted that as the crude pyroligneous acid liquor is drawn off to the copperstill there is an accumulation in said tanks of raw tar and oils, and these are drawn ofi at suitable intervals, by means of pipes, and transferred to a tar still 13,

which is provided with heating means, such as a steam coil H The raw tar and oil is here distilled, the distillate passing to a condenser C, and thence to a settling tank 14, where the oil is drawn'oif through a pipe 14 and the pyroligneous acid liquor is conducted by a pipe 20, and is introduced into the apparatus for carrying out the main process at any point in advance of the receptacle in which the admixture of lime takes place. In this instance the pipe 20 is shown as leading to the storage tank 7 in Prior to our invention, it has been customary to draw off the tarry residue from the tar still 13, and the tarry residue from the copper still 6, to a fuel tank, from which it was used as fuel, or for other purposes. In carrying out our process, however, we proceed to-a further treatment of the tarry residue in thetar, still and in the copper still as hereinafter fully set forth.

The tarry residue in the tar still 13, is subjected to-the action of water, heat suffieient for the. distillation of the water and agitation, and this is accomplished preferably by injecting into the bottom of the mass live steam or superheated steam, and causing it tobubble through the mass; The steam is advantageously injected by means of a pipe or pipes 21, controlled by suitable 'cocks 22, and connected with a steam supply.

The steam agitates the tarry residue very thoroughly and the water condensed therefi'om unites. with the acetic acid present in the tar, by reason of the aflinity of acetic" acid for water, and the heat of the steam,

' The heavy pipes 27 at the bottom of the tanks,to a pipe 1 denser C. We have found in practice that I the treatment of the tarry residue by the action of water, heat and agitation and preferably by the introduction of live steam,

tends to break up the tar, to bring the water into an intimate relation with the particles thereof, and thus to extract therefrom considerable quantities of acetic acid, and a considerable quantity of oils which are not and cannot be extracted by the ordinary distillation of the raw tars. Where live steam is used, should the condensation of the steam not provide suflicient quantities of water addltlonal quantities .of water are added when desired'to facilitate the extracduced t rough the pipes 21 at the bottom of the tarry mass for the purpose of agitating 1t, and bringing the water into intimate relation with the particles thereof, the heat necessary for the vaporization of the acid water being supplied by the steam coil H or other heatlng means. ,Or in some cases We may employ any, well known mechanical meansto produce agitation of the mass, in conjunction with the introduction of water and the application of heat for vaporizing the same. In any case we prefer to continue the treatment until an amount of watery distillate is passed from the still considerably in excess of the contents of the still and until practically no more acid is passed over, and

this distillate is referably collected in sepa-- rate settlin ta s 16, 17 and 18; Pipes 23 and 23 lea from the condenser to the tank 14, and to the tanks 16, 17 and 18 respectively, and are controlled by valves, so that the distillatefrom the o eration now being described can be shut o from the tank 14 and led to the settling tanks 16, 17 and 18 se aration between the solution of acetic acid, and the oily matter which in about the time mentioned, will separate into a layer of heavyoil below the acid liquid, and a layer of li ht oil above the same. The light oil will he drawn off from each tank by means of a suitable swing pipe 24 or other suitable means, and connecting pipes 25, to a pipe 26. oils will be drawn off, as through 28. The acid liquor is drawn ofl separately free from oil, as through pipe 29, and if desired or found necessary it may be assed through a filter, indicated at F and into a pipe 30, which conducts it to any desired point in the apparatus for carrying outthe main process, in advance of the receptacle in which the lime is added. In the present instance thepipe 30 leads to the storage tank 7, and a branch pipe 30 therefrom is shown which leads to one of the primary settling tanks (tank 4) suitable valves 30*, .80 being rovidedto control said pipes. When the iquid is conducted by pipe 30 to the storage tank 7 (in which case valve 30 is open and valve 30 is closed), it is treated with the distillate from the copper still as previously described to separate the alcohol and the acetic acid (as gray acetate of lime). The tarry residue remainin in the tar still is then run off to any suitabde receptacle to be used as fuel qr for other purposes, by means of the pipe r It has been found in practice that the acetic liquor obtained from the tars as just described, contains a certain amount of coloring-and foreign matters, (the color of which tends to deepen as the liquid stands) and that this colorin and foreign matter injuriously-aifects the color and quality of the acetate of lime obtained therefrom. The acetate produced from the distillate from the copper still is slightly above the commercial requirements of gray acetate of lime and the said acetic liquor obtained from the tars can be introduced into the tank 7, as before described, without carrying the resulting acetate below commercial requirements if its percentage in the liquid introduced into the lime lee still is not too great.

We prefer to employ a separate storage tank 7 (see Fig. 1) to receive the acetic liquor,

where it is introduced at this point in the' main process, said tank 7 being connected with the agitator 8 by pipe 30 having a controlling cock 30 while tank 7 is connected to the agitator 8 by a pipe 8 having a cock 8 for controlling the same. By this means proportionate quantities of liquor can be drawn from tanks 7 and 7 (say 85 per cent. from tank 7 to 15 per cent. from tank 7) in which proportions the color and quality of the resulting acetate is not injuriously "affected by the presence of the coloring and foreign matter in the acetic liquor coming from pipe 30. It has also been found in practice, that if the acetic liquor obtained from the tars in the manner-described, be subjected to another distillation before being mixed with the lime the coloring. and foreign matter referred tois practically eliminated. This additional distillation may be accomplished separately, as by passing the acetic liquor from settli tanks '16, 17 and 18 through an additionalstill and con-- denser as indicated in Fig. 1, before it is conducted to tank 7. In said figure we have shown a still 50, and condenser 51, for this purpose, the still bein connected to pipe 30 by a pipe 52 provided with a cock 53, and the condenser 51 being' connected to pipe 30, by a pipe 56 having a cock 54 therem, a suitable cook 55 being provided in ipe 30, between the pipes 52 and 56. In t is case the acetic liquor can be conducted directly to tank 7, or otherwise treated to produce acetate of good quality. Where it is not desired to employ a separate still for this ur: pose substantially the same results, of ehmihating the coloring and foreign matter from the acetic liquor in the settling tanks 16, 17 and 18 can be obtained by introducing the liquor from pipe 30, into the apparatus for carrying out the main process so that it will pass through the main copper still 6. In Fig. 1 we have shown a branch pipe 30 connecting the pipe 30 with one of the primary storage tanks (in this instance tank 4) said pipe being provided with a cock 30 and the plpe 30 being provided with a cock 30 between pipe 30* and the storage tank 7. By opening cock 30 and closing cock 3O the liquor will pass from settling tanks 16, 17 and 18 to tank 4 and thence through the copper still 6, and be redistilled and admixed with the distillate from the pyroligneous liquor, and be carried on through the other steps of the process. In case the liquor is carried through pipe 30 the cooks '53 and 54 would be closed to cut off communication with still 50, or the still 50 omitted altogether.

. There is also a considerable accumulation of tarry matter in the copper still 6,.which as before stated is run for considerable periods continuously. When the tarry matters have accumulated to such an extent as to render it desirable to discharge the still the connection between the still 6 and the settling tanks 2, 3, 1 and 5 is closed, and the tarry residue is treated in the manner previously described by the action of water,

heat and agitation, and preferably by the introduction of live steam at or near the bottom of the still as by means of pipes 21, 21 connected to a steam supply pipe and provided with suitable cocks 22", 22. The distillate from this tarry residue which contains a much smaller quantity of oily matters, but which contains water and acetic acid, is led preferably to the settling tanks 16, 17 and 18, where it is settled, after which the acetic acid liquid is'led (through the filter F if desired) to the desired point in the apparatus for carrying on the main process, as heretofore described, and passes through the steps of the process for the separation of the alcohol, and the acetate of lime, therefrom with the main portions of the products. a

' denser 51 for this bottom of the still.

' In somecases where the amount of oil present is extremely small, the watery distillate from the tarry residue in the still 6, may be turned directly into the storage tank 7 or may be passed through a filter F, if preferred, to eliminate the small quantity of oil present, before. passing to the tank 7. Suitable pipe connections provided with cocks 40 and 41 will preferably be provided to enable the operator to control the discharge from the condenser C in either of the ways indicated. I

After treatment as above described, the residue of tar is conducted from the still 6 by pipe f, to a fuel tank or other receptacle. Actual demonstration has established that by our improved process, we obtain substantially 15 per cent. more acetate of lime from a given quantity of wood, than is pro-' duced by the processes now in general use, effecting a very considerable saving in the cost of production of the gray acetate and a corresponding increase in profit.

In Fig. 2 we have illustrated a form of apparatus for carrying out a sub-process of our main process.- Where it is not desired to treat the tarry residues collectin in the tar still 13 and copper still 6, direct y there-.

in, as hereinbefore set forth, the tar residues may be run off to a storage tank, or directly to a separate still 15, which is provided with a heatin coil H and steam pipes 121, 121 contro ed by cocks 122, 122 and connected to a suitable steam supply pipe, said pipes 121- extending to or near the The action of the steam on the tarr residues will be precisely as previously escribed, and the vapors containing acid liquor mixed with oil pass through the condenser C and thence to settling'tanks 116, 117 and 118 where the liquid is allowed to stand for about twenty-four hours, as before described. The oils are then separated'from the acid liquor, as be-. fore described and the acid liquor is led (through filter F if desired) to storage tank 107. If it is desired to eliminate the coloring and foreign matter before referred to the liquor from tanks 116, 117 and 118'can be redistilled before passing to the tank 107. In Fig. 2 we have shown a still.50 and conurpose, the still 50 being connected b t e pipe 52 with the pipe f from the ter F said pipe being provided with a cock 53*, the condenser being connected by a pipe 56 with the pipe f, which pipe 56 is provlded with a cook 54:, a cock 55 being provided inpipe f between the pipes 52 and 56". From the tank'l07, the acetic liquor is led to the lime mixing tank 108, where thelime is added, and the mass agitated. The resulting liquor is then drawn off into a lime lee still 109 and distilled, the purpose of this being to drive off some water and oils to improve the purityof the acetate of lime, the waste water and oils distilled off through condenser C going to waste. If preferable the distillate from storage tank 107 is carried direct to the lime lee still 109, where the alkali is added and agitated by a stirrin device in the still. The liquid left in the li p taining acetate of lime is drawn off into a settling tank 110 from which theclear liquid is drawn off to an evaporating pan 111, and

me lee still and con evaporated to dryness, after which the acetate of lime is discharged onto. a' drying floor 112, and dried preparatory to shipment.

It is obvious that in the use of apparatus for carrying our process into effect, the

tacle to another, as before described, will e efiected by gravity where this is practicable and where it is not, suitable forclng devices or pumps, or other preferred means which are not shown in the diagrammatic views of the drawings, will be employed where necessary or deslrable.

What we claim and desire to secure by Letters Patent is.;--

1. In a process for separating the products of the destructive distillation of wood, the sub-process whichconsists insubjecting the residual tar and oils to the action of heat and agitation with the addition of water, to eliminate acetic acid, and oils, and distilling the watery liquor, separating the oils from the distillate and-treating the watery acid liquor freed from oils, 'for the recovery of acetic acid.

2. In a process for separating the products acetic acid.

3. In a process for separating the products of the destructive distillation of wood, the sub-process which consists-in subjecting the residual tar and oils. to the action of live steam under pressure introduced, below the surface thereof to extract the acetic acid, and oil remaining therein, distilling the watery liquor so lproduced, and collecting the distillate, sett ing the distillate -for a considerable period, to effect a substantially I complete separation of the oils therefrom, distilling the acetic, liquor to free it from coloring and foreign matter, mixing the distillate with lime, distilling the mixture'qand evaporating the resulting liquor to recover:

gray acetate of lime.

4.. Ina process for separating theproduets 80 transferring of the liquids from one race of the destructive distillation of wood, subjecting the residual tar and oils obtained from the usual process for the separation of Wood alcohol and acetic acid, to the action of heat and agitation with the addition of water to recover additional quantities of acetic acid and oils, distilling the watery liquor and collecting the distillate, separating the oils from the distillate, adding the distillate to the products obtained from the destructive distillation of wood, and treating the resulting material for the production of wood alcohol and acetic'acid in the form of acetate of lime, whereby additional quantities of acetate of lime are recovered.

5. In a process for the separation of the products of the destructive distillation of wood, subjecting the tarry residue, after the distillation of the pyroligneous acid liquor, to the 'action of heat and agitation with the addition of water, to recover additional uantities of acetic acid and oils, distilling t e watery liquor and collecting the distillate, separating the oils from the distillate, introducing the distillate, freed from oils, into the product from the destructive distillation of wood, subjecting the tarry residue, obtained from the first distillation of the raw tars separated from the pyroligneous acid liquor prior to the distillation of said liquor, to the action of heat and agitation with the addition of water and distilling the' watery liquor, collecting the distillate, separating the oils therefrom and adding the distillate freed from oils, to the product from the destructive distillation of Wood, and treating the products from the destructive distillation of wood, so augmented, for the recover of wood alcohol and acetic acid in the orm of acetate of lime, whereby additional quantities of acetate of lime are secured.

In testimony whereof we aflix our signatures, in the presence of two witnesses.

THOMAS H. KENNEDY. FRED J. HECKEL.

Witnesses V. L. PORTER, C. L. FAUST, Jr. 

